1. Field of the Invention
This invention relates to a saw chain sharpening tool, and further and more particularly to a portable tool used in sharpening saw chain cutters.
2. Description of the Prior Art
Portable electric grinders with guide attachments for aligning the tool with the saw chain are known in the art. It is also known in the art to use the flat plate of the tooth of a saw chain as a planar reference point in locating the sharpening position.
Because of the need for a portable yet easy to use tool with which loggers or homeowners can accurately sharpen their saws, many attempts have been made to fill these needs, making the field somewhat crowded. Two recent patents, U.S. Pat. No. 3,354,753 issued to P. H. Kennemore and U.S. Pat. No. 4,019,407 issued to P. J. Penberthy, are attempts to use portable electric tools with attachments designed for use in sharpening saw chains.
The Kennemore patent shows a fixture which attaches to the chuck of a portable electric tool which has a pair of laterally spaced planar surface members with an elongated opening therebetween for viewing the sharpening operation. During the sharpening operation one of said planar surfaces rests on the top plate of the tooth being sharpened, the tool being properly aligned by use of angle marks on the top surface of the planar members.
The Penberthy patent shows a fixture which attaches to the grinding bit of a portable electric tool which has a guide portion consisting of a pair of surfaces and a central opening for viewing the sharpening operation. During the sharpening operation the surfaces rest on the top plate and depth guage of the tooth being sharpened, the tool being properly aligned by use of angle marks on the top surface of the guide surfaces.